Nova has a feature whereby it will provide instance host names that cloud-init
can extract and use inside the guest, i.e. this won't happen without cloud-
init. These host names are fully qualified domain names (FQDNs) based upon the
instance name and local domain name. However, as noted in bug #1698010 [1], the
domain name part of this is based up nova's 'dhcp_domain' option, which is a
nova-network option that has been deprecated [2].
I've started work on a fix [3] that will allow us to retrieve this information
from neutron instead, uncoupling us from this legacy option. However, some
commentators have pointed out that this may not necessarily be what we want to
do: a FQDN is a hostname and domain name, and using one as a hostname may not
be that clever nor correct.
My networking fu isn't strong enough to deliver a verdict so I'm hoping someone
else can make my mind up for me: do we want to migrate this feature to neutron,
or do we want to stop using FQDN and just use instance names?
Cheers,
Stephen
[1] https://bugs.launchpad.net/nova/+bug/1698010
[2] https://review.openstack.org/#/c/395683/
[3] https://review.openstack.org/#/c/480616/